Electromagnetic drive

ABSTRACT

Disclosed is an electromagnetic drive, comprising and armature that can move electromagnetically back and forth. The movement of the armature drives a valve of an internal combustion engine. The ratio of the depth of the yoke in relation to the width of the yoke of the electromagnets and the length of the armature in relation to the width of the armature is greater than 1.5 in order to reduce the power consumption of the drive.

BACKGROUND OF THE INVENTION Field of the Invention

The invention concerns an electromagnetic drive having thecharacteristics of the preamble superordinate claim 1.

DE 197 120 63A1 or the publication of the corresponding internationalapplication PCT/EP 98/01719 1 describes an electromagnetic drive.

The paramount objective in the design of such drives is to achieve thesmallest possible losses in the air gap and in the magnetic circuit ofthe electromagnet and the least possible weight of the moveable mass. Inorder to achieve said objective, an integration of the armature into anorientable armature lever in accordance with the cited state of the art.Since the laws of physics relate the mass of a rotational system is tothe square of transmission, the ratio of the distance of the armaturefrom the fulcrum of the lever to the distance of the point of action onthe element to be motivated by the fulcrum was chosen to be less than 1.

SUMMARY OF THE INVENTION

The purpose of the invention is to provide a further possibility ofreducting the electrical losses of the drive and of the weight of themotivated mass.

The disclosure describes drives in accordance with the cited state ofthe art but also those drives, whose armatures describe a point to pointmovements.

The subordinate claims contain advantageous alternative embodiments ofthe invention.

The minimum one electromagnet described in the disclosure must have atleast one active; that is, lift producing, pole.

Preferably, the armature is driven by two electromagnets; however, aswill be shown in the following, the drive is also realizable by means ofa coil, that practically cooperates alternatively with the differentpoles. Preferably, the electromagnet or electromagnets are designed asbipolar; however, electromagnets with more than two poles are alsoconceivable; for example, even pot-shaped magnets. In the case of abipolar design and orientable bearing of the armature a design is alsopossible, in which only one of the poles is active; that is, directlyeffects an attraction of the armature—thus performs lifting work—whilethe other pole provides only the return flux over the armature bearing.In the combination of these modalities a solution using oneelectromagnet and one active pole is conceivable.

The following considerations resulted in the inventive dimensioning ofthe drive: Principally, the armature mass is determined by therequirements in accordance with maximal drive power. Here, the limitingdimension is the flux density in the magnetic circuit at whichsaturation occurs. Dimensioning of the armature is determined by theoverall yoke breadth and the yoke length. The overall yoke breadth isthen again determined by the distance between the two limbs, which isdetermined in accordance with considerations of magnetic scatter loss.In general, the overall yoke breadth should be kept as small aspossible. Optimization of the armature weight is now possible in thatthe yoke breadth is kept as narrow as possible with the deepest possibleyoke depth. In order to minimize the weight, a ratio of yoke depth tothe overall yoke breadth comes into play, which is unusual for magnets.Conventionally, magnets are generally dimensioned in such a way that theratio of breadth to length results approximately in a square. In orderto achieve minimal armature weight in the invention, a ratio is selectedthat is greater than a factor of 1.5, in particular greater than 2 andpreferably greater than 3. The result is thus a relatively long, thinarmature that must be appropriately mounted.

By dimensioning a long magnet, the magnet can be over-dimensioned in thepower balance which has special advantages; for example, for the openingmagnet of the exhaust valve or the shutting magnet of the inlet valve,which must overcome the forces of the gas. In the familiar system usingan armature lever described above the torsion bar is used simultaneouslyas the bearing point for the armature lever. In this case, the torsionbar is subjected to an additional flexural load. When dimensioning along magnet with a correspondingly long armature, according to theinvention this is not possible; therefore, pursuant to a furtherembodiment of the invention, the armature is connected via one orseveral armature levers to a tube, which is mounted at least on bothsides and absorbs the bearing force. The torsion bar can be situated onthe inside of the tube and it is completely unburdened by additionalflexural forces.

Along with the longitudinal expansion of the valve and the cylinder headthe system must be adjustable to the relatively large tolerances of thevalve, the valve seat, the cylinder head and the drive housing. Toachieve this, it is recommended that the housing is rotatable around theaxis of rotation of the armature tube or even around that of the torsionbar or around another axis of rotation away from the armature thehousing lies in a bearing pit and is fastened via a cushioningcounterbearing. Adjustment is done, for example, by means of two nuts,whereby one nut represents the so-called anvil and is shifted to adjustand the second nut is used for the purpose of securring.

A further enhancement is represented by an arrangement of the magneticcircuit whereby grain-oriented material is inserted, which is economicaland reaches saturation in the region of 1.9 Tesla. At the onset ofsaturation, normal magnet material exhibits a flux density of 1.4 Tesla.Thus, a considerable power increase per unit of area is possible andthis results in smaller magnets and reduced armature masses.

A long magnet with high pole area has, however, disadvantages ininductivity and thus in time response; therefore, it is recommended,division of the yoke limb and insertion of two coils. The constructiondescribed for the long magnets additionally has the advantage tht thestructural width is relatively small, which again permits a relativelylow cylinder head. A cost factor is the layout of the coils. Frequently,the yoke is divided when inserting the coils into the magnetic circuit;this means losses at the junctions. In the inventive design the coilsare constructed in such a way that they can be installed in the windowbwteen the two limbs of the yoke. Correspondingly the maximum width ismeasured.

A particular problem is presented by the requirements for small timeconstants with relatively large magnets with corresponding inductivity.A small time constant is required for the purpose of position adjustmentand is thus achieved in that the valve is seated with low speed. Forthis to happen, it is necessary that the magnetic circuit reacts quicklyto the respective control signals. This is achieved in that, asdescribed above, by the partitioning of the yoke several coils are usedand are switched in parallel. For example, four coils can be providedwhich can be switched together in parallel. Since these coils, incomparison to one coil, have the same time constants, in less than aquarter of the time the required linkage/permeation is achieved. The jobof the magnets is, on the one hand the performance of the lift work forthe purpose of the mechanical and the gas losses. On the other hand, aclosed or an open valve position should be achieved by the armature inits terminal positions. Over 70 percent of the operating cycle is usedfor the closed position. In order to keep the required holding energylow the coil current is switched/clocked. However, a separate holdingcoil can be used. By using said holding coil with the appropriatelylarge number of windings the holding energy; that is, the output, can bedrastically reduced. In order to provide for a favorable heat removalthe coils are relatively thin and have a relatively large surface thanksto the advantage of the long magnet. In addition, filler pieces betweenyoke and coil body can be installed for enhanced heat removal. Saidfiller can be laminated and made of material that has good heatconducting properties but it can also be magnetic material for thepurpose of reduction of the ferric [magnetic] losses. There are alsopossibilities for combining of both methods. The coils are preferablyimbedded into the base body and they can in certain cases also beextruded into it.

A large problem is presented by the control of the various longitudinalexpansions undergone by the cylinder head and the valve during warm-up.Per the state of the art hydraulic elements are frequently used to evenout the play or magnets with large air gap are used. The elements usedfor hydraulic compensation of play are very expensive and are limited incompensating play, since there is also the risk that the drive isoperated outside of its centerline. As in the state of the art describedabove, an overstroke spring can also be used. With the additional use oftemperature compensation in the housing or in the valve, the overstrokeis relatively slight; for example, it is limited to a couple tenths of amillimeter and has a less powerful effect on the holding energy at arelative low translation ratio of magnet to valve axis. This overstrokespring has the advantage that at seating; that is, on closing of thevalve, generally only the valve mass acts as an impact load or stress.The remaining mass is decoupled by the overstroke spring. Preferably,the overstroke spring is constructed so that the majority of the masssits upon the small arm of the lever and thus does not directly flowinto the effective mass. At the same time the magnet can be brought ontoa smaller air gap. The remaining air gap must be dimensioned so that itovercomes the actual valve seal and a temperature expansion without thearmature being fully supported. If the armature rests before the valvecloses, there would be no valve seal.

There are various possibilities for the transfer of the drive force fromthe armature to the valve. The least magnetic power and motivated massesand thus also energy requires a direct coupling of the valve to thearmature movement.

It is, however, also possible to uncouple the valve via its own,conventional valve compression spring. In this instance the torsionspring and/or a tension or compression spring can provide the necessarycounter force. These solutions offer advantages in assembly, but aredisadvantageous because of the larger masses motivated, greater magneticforce, and higher energy requirements.

The invention will be described in more detail using the followingexamples of embodiments.

Wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: depicts a lateral view of an electromagnetic drive;

FIG. 2: depicts a detail of FIG. 1;

FIGS. 2a and 2 b: depict the construction and bearing of the armature;

FIG. 3: depicts the electromagnetic drive of FIG. 1 in perspective;

FIG. 4: depicts the possible configurations of the yoke of anelectromagnet;

FIGS. 5, 5 a, and 5 b and 5 c: depict alternative drive possibilitiesfor the valve shaft;

FIGS. 6 and 7: depict special armature constructions;

FIG. 8: depicts various arrangements with two torsion springs;

FIG. 9: depicts another construction of an electromagnetic drive;

FIGS. 10a and 10 b: depict the comparison of two drives withlinear/point-to-point armature movement once with short and once with along (deep) armature and the corresponding electromagnets.

FIGS. 11a to 11 g: various possible forms of the electromagnet(s).

DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIG. 1 an armature lever 1 is connected with a section of tubing. Ittransfers the forces for activation of the valve via an overstrokespring 3 on the bearing housing 1 f with a bearing 4 on a valve stem.The valve stem exhibits a flexible valve stem element 6 a. Theoverstroke spring 3 requires a prestressing; it can be adjusted using anadjustment element, for example an eccentric 5. A second stop 5 a limitsthe overstroke. The function of the overstroke spring is described inmore detail in the state of the art mentioned above.

The magnet systems are comprised of a closing magnet 7 and an openingmagnet 8. In the embodiment example the opening magnet 8 is depictedlarger than the closing magnet, because it must produce a greaterlifting force in the exhaust valve on opening in order to overcome theforce of the gases. Both magnet yokes are constructed in one piece andmanufactured out of grain-oriented material, which allows only slightferric [magnetic] losses with high flux densities. In areas with achange of direction of the yoke the yoke can exhibit a expansion togreater cross-sections. A smaller cross-section In and the grainoriented optimal flux direction can be incorporated into the yoke limbs.The magnets each have two double coils 9 and 10. Said double coils arepresent double in each yoke limb, if the yoke is partitioned. The doublecoils are switched in parallel inorder to make produce reducedinductivity and thus achieve faster time response. Nevertheless, theycan also be operated as single coiles or in series circuit.

FIG. 4 depicts two possible yoke arrangements with an partitioned 7 cand a closed limb 7 b. The partitioned limb sections are enclosed by twodouble coils 12 and 13 a. In this case one or even two output stages canbe used. The coils are connected in parallel. It is also conceivable,however, that they can be shorted entirely or in part for the purpose ofbraking the armature.

In the more advantageous configuration with undivided limbs 7 b of theyoke 7 a holding coil 13 c is mounted on it.

The magnets 7 and 8 are fastened in FIG. 1 each via a centering pin 12.Said pin protrudes on both sides into two housing plates of which onlythe rear one 13 is visible. The magnets are fixed via relatively longbolts 14, whereby the bolts between the yokes must not be magnetic.Tensioning is done after the magnet yoke is adapted to the armature sothat uniform air gaps result. Better heat removal for the magnet coilsis achieved by appropriate formal design of the plates. The coils areimbedded by appropriate elevations 15 of the base plates 13 and 13 a sothat the result is satisfactory heat removal on both sides.

The entire drive is mounted on both sides in bearing supports consistingof extensions 20 of the actuator box (21). Said extension is depicted inbroke lines behind the magnet 9. The counter-bearing is formed byappropriate recesses in the housing 13.

The cushioning counter-bearing 22 is fastened to the actuator box 21with two screws 23. All drives of a cylinder bank are housed in saidactuator box.

The housing 21 is adjusted and fixed using two nuts. Said arm is behindthe valve shaft 6, 6 a and the centering of the valve fork 6 b is shownin broken lines and enlarged in FIG. 1a. The arm 24 of the housing 13 isfixed with two bolts 25. When adjusting, they are turned on the screw 26until the correct adjustment of valve and armature positon isestablished over the lift sensor 27. For fixation the upper nut iscountered. As an alternative, for example, two screws can be used,whereby, again, the first screw forms the anvil for the housing and thesecond screw is used for securing.

A torsion spring 16 lies in the bore of the armature tube 2. Thearmature is shown in more detail in FIGS. 2a and 2 b.

FIGS. 2a and 2 b illustrate the armature tube 2 in sectional depiction.In FIG. 2a it is show connected to three lever sections 1 b to 1 dcomprising the armature lever. These three lever sections include thedepicted armature 17. Said armature 17 is interrupted by a valveactuation element 18, that is comprised essentially of the overstrokespring 3, the bearing housing 1 a and the bearing 4. The armature 17 andthe valve actuation element 18 are welded to the lever sections. Thetube 2 is mounted for the purpose of carrying the relatively largearmature forces on both sides at parts 19 and 19 a of the housing plates13 and 13 a as shown in FIG. 1. Preferably roller bearings are used andthe bearing is comprised of external bearings. The torsion bar 16(torsion spring) running through the tube 2 can be completely relived offlexural stresses by these bearing points. It is connected on the oneside (left) with the tube 2 and restrained on the other side in the part19 a. In this situation no axial play exists.

The length (depth) 1 and the width b of the armature are drawn in FIG.2a. The magnet yokes situated opposite the armature have the respectivedimensions.

FIG. 2b shows a simplified embodiment of the armature fastening. Botharmature pieces 17 are welded to only one armature lever 1 e and to thetube 2. The weld points are identified in the conventional manner bywedge-shaped, dark notches. The armature lever corresponds to FIG. 5a.

FIG. 3 shows the arrangement in perspective depiction. The armature tube2 is connected to the magnetically conductive armature lever 1 b to 1 d.Here the connection points formed during the welding process can also beseen. In order that the magnetic flux of the two magnets are notaffected by the armature tube 2 the later is preferably comprised of anonconductor or only weakly conducting or nonmagnetic material. Thearmature 2 is mounted in the bearing points 19 19 a and accomodates thetorsion bar. On the left half of the illustration the long magnet 7 isshown and is sectioned in the anterior portion in order to show thevalve joint 4. The magnet 7 shows a recess 20 a for interruption of theyoke for installation of 2 double coils each. This recess is also usefulfor the overstroke spring, which protrudes into the yoke on liftingmovement. The armature is shown here too at 17. In lieu of the fulll cutout of both yoke limbs a magnetically conductive filler element can alsobe used. In this figure the armature is shown with an interval to thearmature tube 2. It can also abut directly on the armature tube as shownin FIGS. 2a and 2 b.

FIG. 5 shows and alternative valve actuation. The valve is, as is knownin the art, is pressed by a compression spring 30 in the direction ofthe closed position. Here the torsion bar 16 acts against thecompression spring. In the centerline drawn the elastic/spring forcesare shown in equilibrium. The transfer of forces occurs via a roller 31equipped with a roller bearing that is connected to the armature lever 1c. The latter is configured slightly elastic by means of its limb, inorder to reduce the impact load when the valve shaft seats.

In addtion, a compression spring 32 can be attached to a relativelysmall lever arm and used for supporting the torsion rod 16.

FIG. 5a depicts in lieu of the roller a sliding element 33 that iswelded into the armature and can be surface coated on the slide. Thiselement, too, is designed to elastically reduce the impact load.

FIG. 5b depicts a side view. For reduction of the sliding friction onthe valve shaft the compression spring bearing can be mounted in a ballbearing 34.

This and an eccentric bearing of the sliding element 33 effect adesirable valve torsion.

The drives of FIG. 5 and FIG. 5a do not require a flexure zone in thevalve shaft because they themselves can compensate the misalignmentcaused by the swivel of the lever 1 c.

The upper part of the valve shaft 35 is made of a material having lowtemperature expansion; for example, invarsteel and flanged or weldedonto the valve shaft 36. For better temperature dissipation form thevalve disk, the hollow valve shaft 36/37 is filled with sodium. Thedifferential movement between the roller 31, or the sliding element 33and the valve shaft 36/37 between the cold and the operationally warmvalve is considerably less due to the temperature compensation and thusthe bearing stress and the holding energy is considerably low.

FIG. 5c includes a sliding element 39 that is mounted rotatable on ashaft 39 a. Said sliding element corresponds to the conventional camdrive via an oscillating arms or levers. It can also be mounted in aspherical calotte in order to fully adapt to the valve shaft head. Saidsliding element preferably has clamping or tension device so that ontouching down at the time of valve opening a slight surface pressureresults.

FIG. 6 differs from FIG. 5 only by a alternative configuration of thepole 40 of the opening magnet 41 and an appropriate configuration of thearmature 42. The poles 40 are designed stepped—in this instance with twosteps. The armature 42 exhibits on the side facing the opening magnet acorresponding slope such that the armature 42 fits into the opening ofthe stepped poles with a small air gap. For the proper effect of themagnets 41 the widths and depths 40 a and 42 a of the poles 40 and ofthe armature 42 are essential. Thus, characteristic curve formation ispossible with the result that the lifting force of the magnets withlarge air gaps is considerably higher. This configuration of the magnets41/42 is of particular significance in the bearing of the armature bymeans of the roller bearings, since relatively large shearing forcesoccur through tolerances in the armature.

FIG. 7 shows a corresponding configuration of the poles of the closingmagnets 50 and 50 a of an inlet valve drive and of the associatedarmature 52.

The yokes and the armature of the opening and closing magnets of anactuator, particularly of the outlet valve drive can be configured usingthe characteristic curve formation mentioned above.

In FIG. 8 various versions are shown with a second torsion bar connectedin parallel. In FIG. 8a the lever acting on the valve shaft 6 isidentified with 1, the armature with 17, the bearing tube with 2, andthe torsion bar with 16. A second torsion bar 16 a with bearing tube 2 aand a lever 1 e is provided, whereby the elastic forces of said torsionbar 16 e are concentrated via a connector element 60 with the forces ofthe torsion spring 16.

In FIG. 8a a valve spring 30 acts, corresponding to FIG. 5a, on thevalve shaft and the armature movement is transferred by a slidingelement 33 to the valve. Here, too, a connector element 60, transfersthe forces of the second torsion spring 16 a to the lever 1.

In FIG. 8c the valve spring 30 is replaced by the torsion bar spring 16a that grips over the connector element 60 under the valve shaft head61. The torsion spring 16 acts via a sliding element on the valve shaft.

In FIG. 8d the connector element is not mounted rotatable on the lever 1c but is rigidly connected to it. The transmission element is a flatspring 60 a that likewise grips under the valve shaft plate 61.

In FIG. 8e the second lever 1 c is not mounted on a tube. Here, abearing piece 63 is connected on the one side with the tube 2 of thetorsion spring 16 and on the other side with a bearing of the torsionbar 16 a. The shear forces are braced at a bearing point 64.

FIG. 9 shows a configuration in which a main lever 70 is deviated by anadjunct lever 71 from the two electromagnets 72 and 73. The levers 70and 71 are connected to a tube 74, in whose inside the torsion spring 75is housed. The adjunct lever 71 carries the armature or represents thearmature. It is configured as a long magnet.

The transfer of forces to the valve shaft 76 occurs, analogous to FIG.1, via an overstroke spring 78 fastened at 77 to the main lever 70 atwhich at the anterior end of the main lever 70 two stops 79 are situatedfor the purpose of limitation of deflection. Here, too, a flexure zone76 a is provided in the valve shaft.

This arrangement exhibits an extremely low structural height, providesbetter use of the magnet length, has a minimal weight and decoupling ofthe overstroke spring from the armature is provided.

FIGS. 10a and 10 b: depict the comparison of two drives with linear,point-to-point armature movement, once with short and once with a long(deep) armature and the corresponding electromagnets.

The magnets and armature in both Fig. are designed for the same fluxdensity. The following dimensions apply:

FIG. 10a FIG. 10b Central Yoke Breadth b b/2 Leg Breadth b/2 b/4 CoilThickness K K Armature Height h = b/2 b/4 Magnet Breadth L 2L ArmatureSurface (2b + 2K) L (b + 2K) 2L Armature Volume (2b + 2K) L × b/2 (b +2k) 2L × b/ = (b + 2K) L × b/2

One can see that for FIG. 10a there is a dependence of 2 b (in thebrackets) and for FIG. 10b a dependence only on 1×b; thus, the armaturevolume and therefore the armature weight is clearly less.

With a comparable design corresponding to FIG. 10a the resultingarmature weight was 72 g and in a design corresponding to FIG. 10b thearmature weight was only 47 g.

If one substitutes for b=10, for K=2 and for L=20, then in the case ofFIG. 10a the result is a volume of 2400 (=100%). For that of FIG. 10bthe result is a volume of 1400, thus, approximately 58%. With a 3×lengththe volume is reduced to 48%.

Because of the increased magnet length (depth) the drive must, ifnecessary, be installed in the motor due to space considerations.

It must be mentioned that the inventive deep designed yokes of theelectromagnets and correspondingly the inventive deep designed armaturedo not necessarily have to be fabricated in one piece but can beassembled from two or several pieces; the magnets can also be assembledfrom several partial magnets, whereby one or several armatures can beprovided.

In the figures described above one torsion bar is provided for theproduction of at least part of the elastic force. It is, however, in thecase of this invention also possible to produce both elastic forces, forexample, by using coil springs. In the example of FIG. 5a the, a springarranged in the valve axis acts on the lever 1 c from above. A slightload of the lever bearing is achieved in this way.

FIG. 11 depicts various other possible embodiments for theelectromagnet(s) as in the foregoing figures.

FIG. 11a depicts two three-pole electromagnets 100 and 101, which aresituated opposite the armature 102. FIGS. 11b and 11 c depict views fromabove of the magnet poles. The winding 103 can be produced to correspondto FIG. 11b or as a pot-coil corresponding to FIG. 11c. In FIG. 11d twothree-pole electromagnets are depicted, whereby in this case one pole104 is not active; that is, it is does not contribute to the liftingwork. Also and analogous thereto is the possibility of executing theelectromagnets as two-pole magnets and then to use only one of them asthe active.

In the example of FIG. 11e only one winding 105 is provided, wherebydepending on the location of the armature 106, pole 107 or 108 iseffective. If the armature is brought into the proximity of pole 107 or108 by the effect of the elastic forces, then the winding 105 can beswitched on and the armature will accelerate in the direction of therespective pole. In order to achieve a buildup from the intermediateposition either the intermediate position must be asymmetrical or thepole of an electromagnet must be more powerfully designed. Finally, inFIG. 11f a combination of FIG. 11e with the use of only one active poleis depicted.

The magnetic circuit 110 of FIG. 11g corresponds to an e-corecorresponding to FIGS. 11a and 11 b.

The pole interval of the external limbs 111 and 112 is as small aspossible in order to keep the width 113 a of the armature 113 as smallas possible. For the purpose of reducing the scatter flux between themiddle limb 114 and the outside limbs and in order to illustrate a largeangular space the external magnetic circuit 115 and 116 is opened up.The middle limb 114 is preferably comprised of grain-oriented materialand is interlocking; that is, dove-tailing 117 is inserted into the yokeor is welded to it.

The armature thickness in the case of the e-magnets approximates that ofthe thickness of the external limb 115 and 116, which again is about 50%of the width of the middle limb 114. Thus, the thickness of the armature113 is only about 50% of the armature thickness of a U-magnet. Withoutspecial procedures the pole interval in the e-magnets is large than inthe U-magnets. Through the procedure of expansion or opening up thisdisadvantage can be minimized. The effective savings in weight in thistype of magment is about 40% compared to the U-magnets.

A further advantage is to be found in the co-employment of the middlelimb 113 as the core of the winding 119. This is particularlyadvantageous in the case of strip or band coils. Thus, an excellent fillfactor can be achieved. This is of essential significance, since thedissipation rate of the coil is very strongly dependent on the angularspace and the fill factor.

In the case of the e-core there is yet another opportunity to use fourtorsion screws 118 in contrast with the three in the U-core, which isvery favorable with respect to the symmetry of the expansion force.

With respect to the execution forms; that is corresponding to FIG. 11with approximating pole terminals towards the armature, it must be notedthat the definition pursuant to Claim 1 Depth to Width of the yokegreater than 1.5, etc. refers to the yoke width at the ends of the yokesand not to the yoke width lying more distally.

While the invention has been described with reference to the preferredembodiment thereof, it would be appreciated by those of ordinary skilledin the art that modifications can be made to the structure and method ofthe invention without departing from the spirit and scope of theinvention as a whole.

What is claimed is:
 1. An electromagnetic drive having a movablearmature (17) that can be electromagnetically moved laterallypoint-to-point and which is moved by at least one electromagnet (7, 8)into final positions, whereby a valve element (6), of an internalcombustion engine, is driven by the movement of the armature (17),characterized by the fact that the ratio of the depth to the width ofthe yokes of the electromagnets (7, 8) and the ratio of the depth to thewidth of the armature (17) are both greater than 1.5.
 2. Anelectromagnetic drive according to claim 1, characterized by the factthat two elastic forces (18) are mounted opposite one another and actupon the armature (17) and position the armature (17) in an intermediateposition without the action of excitation currents.
 3. Anelectromagnetic drive according to claim 2, characterized by the factthat with a swivel-mounted armature the two elastic forces are formed atleast in part by a torsion spring (16).
 4. An electromagnetic driveaccording to claim 2, characterized by the fact that that the twoelastic forces are formed at least in part by traction and/orcompression springs.
 5. An electromagnetic drive claim 2, characterizedby the fact that a valve spring (30) is provided whose elastic forceacts upon the valve shaft (36) in the direction of the closed positionof the valve.
 6. An electromagnetic drive according to claim 1,characterized by the fact that with a rotatably mounted armature (17) oran armature (17) supported by a rotatably mounted lever (1) the armature(17) or the lever (1) is connected with a rotatably mounted tube (2) ortube-like part, that said tube (2) or part is connected with a torsionspring (16) running at least partially in the tube or part and that thetube (2) or part is mounted externally.
 7. An electromagnetic driveaccording to claim 6, characterized by the fact that the armature (17)is connected to the tube via at least two partial levers (1 b to 1 d)arranged parallel to and separated from one another.
 8. Anelectromagnetic drive according to claim 6 and characterized by the factthat an overstroke spring (3) is incorporated in the lever (1), viawhich the armature movement is transmitted to the valve element andwhich is rigid for said movement to be transmitted and is only effectiveas a cushion/spring in the event of high stress/load (overstroke).
 9. Anelectromagnetic drive according to claim 6, characterized by the factthat the part of the lever (1 a) that drives the valve element (6)exhibits a joint (4) to which the valve element (6) is connected.
 10. Anelectromagnetic drive according to claim 6, characterized by the factthat the valve element to be driven is the valve stem of a valve andthat the valve stem of the valve is of a flexible design.
 11. Anelectromagnetic drive according to claim 6, characterized by the factthat that the lever (1, 1 a) lies loosely on the shaft (36, 37) of thevalve.
 12. An electromagnetic drive according to claim 11, characterizedby the fact that the lever (1, 1 a) acts upon the valve shaft by way ofa roller (31).
 13. An electromagnetic drive according to claim 11,characterized by the fact that the lever (1, 1 a) acts upon the valveshaft (36, 37) by way of a sliding element (33).
 14. An electromagneticdrive according to claim 11, characterized by the fact that the leveracts upon the valve shaft eccentrically.
 15. An electromagnetic driveaccording claim 1, characterized by the fact that the material of themagnet core (7, 8) and/or of the armature (17) is grain-oriented.
 16. Anelectromagnetic drive according to claim 15, characterized by the factthat the magnet cored of the electromagnets (7, 8) in zones (7 a, 8 a)exhibit a larger cross-section with a change in direction of the yokes.17. An electromagnetic drive according to claim 1, characterized by thefact that the magnet core of the electromagnets is executed in one piece(FIG. 1).
 18. An electromagnetic drive according to claim 1,characterized by the fact that at least on one yoke of a magnet andtowards the pole surface a division of the yoke into at least two yokesections (7 b) is provided (FIG. 4) and that at least two coils (13, 13a) are arranged on said yoke sections and that said coils (13, 13 a) areconnected in parallel (FIG. 4).
 19. An electromagnetic drive accordingto claim 1, characterized by the fact that at least one additional coil(13 c) is arranged on the yoke of the closing magnet (7), said coilserving to hold the valve in the respective position.
 20. Anelectromagnetic drive according to claim 1, characterized by the factthat the magnet core of the electromagnets (7, 8) are retained andarranged between two plates (13) of the housing.
 21. An electromagneticdrive according to claim 20, characterized by the fact that theorientation of the yokes to the armature (17) is rotatable.
 22. Anelectromagnetic drive according to claim 20, characterized by the factthat the coils (9, 10, 11) are in thermal conducting conjunction withthe plates (13) of the housing via the yokes.
 23. An electromagneticdrive according to claim 22, characterized by the fact that fillerelements (15) are provided between the coils (9, 11, 12) and the yokesfor the purpose of heat dissipation.
 24. An electromagnetic driveaccording to claim 20, characterized by the fact that finning or ribbingis provided for heat loss.
 25. An electromagnetic drive according toclaim 6, characterized by the fact that for adjustment of the entiredrive is rotatable around the tube axis or around an axis lying moredistally from the armature.
 26. An electromagnetic drive according toclaim 3, characterized by the fact that the torsion spring (16) isdesigned as a rod with a rectangular cross-section.
 27. Anelectromagnetic drive according to claim 1, characterized by the factthat seen in cross-section, the poles (40 of at least one of theelectromagnets (7, 8)) are designed in steps (40 a) and that thearmature (42) when viewed in cross-section exhibits a thereininterlocking counter-stepping (42 a).
 28. An electromagnetic driveaccording to claim 27, characterized by the fact that the opening magnetof the outlet valve exhibits such a stepping.
 29. An electromagneticdrive according to claim 27, characterized by the fact that the closingmagnet of the outlet valve exhibits such a stepping.
 30. Anelectromagnetic drive according to claim 13, characterized by the factthat the sliding element (30) on the lever (1 c) is rotatable (Shaft 39a) (FIG. 5c).
 31. An electromagnetic drive according to claim 30,characterized by the fact that the sliding element is mounted on thelever by means of a ball and a ball cup.
 32. An electromagnetic driveaccording to claim 6, characterized by the fact that a main lever (70)for actuation of the element (for example, the valve shaft 76) and anancillary lever (71) representing the armature or carrying it, at anangle opposite the main lever (70) and connected with the main lever,are provided.
 33. An electromagnetic drive according to claim 3, furthercomprising a first torsion spring (16) and a second torsion spring (16a) and characterized by the fact that for at least the partialproduction of the elastic force, said first and second torsion springs(16, 16 a) are arranged in parallel to each other.
 34. Anelectromagnetic drive according to claim 33, further comprising twolevers (1, 1 e) and characterized by the fact that each of said torsionsprings (6, 16 a) is connected with one of said levers (1, 1 e) via atube (2, 2 a), whereby the transmitted forces act upon the valve shaftby way of said two levers (1, 1 e).
 35. An electromagnetic driveaccording to claim 33, further comprising a first lever (1) and a secondlever (1 e) and characterized by the fact that said first lever (1) isconnected with said first torsion springs (16) by way of a tube (2) andsaid second lever (1 e) is connected directly with said second torsionspring (16 a).
 36. An electromagnetic drive according to claim 1,characterized by the fact that the yokes of the electromagnets (7, 8)and/or the armature (17) are assembled from two or more parts.
 37. Anelectromagnetic drive according to claim 36, characterized by the factthat several magnets are arranged in sequence opposite which a one-pieceor multiple-piece armature is situated.
 38. An electromagnetic driveaccording to claim 6, characterized by the fact that the range of effectof the forces of the armature or of the lever (3) carrying the armatureon the valve shaft (6) lies outside of the effective area of at leastone electromagnet.
 39. An electromagnetic drive according to claim 1,characterized by the fact that at least one of the magnets exhibits ane-core (110), whereby the ends (111, 112) of the outside limbs runtowards the middle limb (114).
 40. An electromagnetic drive according toclaim 39, characterized by the fact that that the middle limb (114) isthe carrier of the winding (119) (preferably a strip coil).
 41. Anelectromagnetic drive according to claim 39, characterized by the factthat the middle limb (114) is connected with the core (115/116) bywelding and/or by a dove-tail interlocking connection (117).
 42. Anelectromagnetic drive according claim 39, characterized by the fact thatthat the middle limb (114) is comprised of grain-oriented material. 43.An electromagnetic drive according to claim 1, characterized by the factthat the ratio of the depth to the width of the yokes of theelectromagnets (7, 8) and the ratio of the depth to the width of thearmature (17) are both greater than
 2. 44. An electromagnetic driveaccording to claim 1, characterized by the fact that the ratio of thedepth to the width of the yokes of the electromagnets (7, 8) and theratio of the depth to the width of the armature (17) are both greaterthan 3.